The present invention relates to a liquid crystal display device, for example, to technology applicable to a terminal portion layout.
In an active-matrix liquid crystal display device, pixels are each composed by forming, in an area near an intersection of a scan line (hereinafter referred to as a “gate line”) and a video signal line (also called as a source line or a drain line and hereinafter referred to as a “drain line”), a thin-film transistor (TFT) which is turned on by a scan signal from the gate line and a pixel electrode to which a video signal from the drain line is supplied via the thin-film transistor. A display area is where plural pixels are formed. The display area is surrounded by a peripheral area (frame area). The peripheral area includes semiconductor chips, chip-on-glass (COG) terminals, and wirings (terminal wiring lines). The semiconductor chips include video line drive circuits for driving drain lines and scan line drive circuits for driving gate lines. The COG terminals and wiring lines connect the gate lines and drain lines in the display area to the semiconductor chips.
In recent years, the numbers of pixels used in liquid crystal display devices have been increasing as their image resolution is enhanced to improve the recognizability of information displayed on them. Hence, the numbers of drain lines and gate lines used in liquid crystal display devices have also been increasing. Keeping pace with such a trend, the number of signals inputted to or outputted from each semiconductor chip used in liquid crystal display devices and the numbers of COG terminals and terminal wiring lines used in liquid crystal display devices have also been increasing. Against such a backdrop, a technique for forming semiconductor chips and many COG terminals and terminal wiring lines in a peripheral area of a limited size is needed.
In the display area of a liquid crystal display device, an alignment film is laid over a transparent conductive film and, to promote liquid crystal alignment, the surface of the alignment film is rubbed in a certain direction, thereby making it easy to align the liquid crystals in the direction of rubbing (see Japanese Patent Laid-Open No. H9 (1997)-244043).